Optical bleaches



FIPSSQB GR 59039s224 United States Patent This invention relates tooptical bleaches. The compounds of this invention are particularlysuited to use on textile materials.

Optical bleaches are fluorescent compounds that absorb ultraviolet lightand emit visible light. By such action, these compounds improve theshade of both white and colored materials.

Optical bleaches of this invention are adapted to be added to thematerial at the time of fabrication, e.g. at the mill in the case oftextiles or paper, or at a later time. In the case of textiles, theoptical bleach may be added at the time of laundering. If the opticalbleach is added during a laundering step, it maybe added either alone oradmixed with a detergent or other cleansing agent.

According to the present invention, an optical bleach efiect is obtainedby treating a material with 2,4,5-triphenylimidazole (lophine) or2-(3,4-methylenedioxyphenyl)-4,5-diphenylimidazole in sufiicientquantity so as to cause a fluorescence of visible light when the treatedmaterial is subjected to a source of ultraviolet light. The inventionalso encompasses a method of producing a brightening efiect on materialsby applying lophine or 2-(3,4-methylenedioxyphenyl)-4,5-diphenylimidazole in the form of asolution to such materials and drying the treated textile materials.Particularly suited to the present invention is an aqueous solution oflophine or 2-(3,4- methylenedioxyphenyl) -4,5 -diphenylimidazole.

By the term solution, as used in this application, it is meant toinclude a dispersion and not to be limited to true solutions.

The optical bleaches of the present invention are preferably utilized ina solution concentration ranging from about 0.0001 to about 0.1% byweight of the solution. Concentrations of less than about 0.0001% do notusually improve textile whiteness and concentrations greater than about0.1% are presently uneconomical and do not generally noticeably improvethe whitening effect on the textile in proportion to the increasedamounts of optical bleach in the carrier.

The following examples illustrate the invention:

Example I Test samples of the following textile materials were scouredin the solution of sodium carbonate to remove all finishes which areplaced on the'cloth during manufacture:

Percale, 180 x 180, 100% cotton Acetate rayon crepe Nylon marquisetteDacron polyester-cotton broadcloth The fabric samples were then washedin a solution composed of 50 grams of detergent that did not initiallycontain a brightening agent, 0.5 gram of lophine and 17 liters of water.

The water portion of the washing solution was heated to 140 F. In orderto facilitate a quick dispersion throughout the washing solution, thelophine was initially dissolved in a small amount of water made slightlyacid with formic acid and then added, along with the deter-- gent, tothe wash water. This solution was then transferred to a washing machineand agitated for five minutes. The sample textile 'materials were placedin the washing machine and washed for 30 minutes. The temperature @LHWQHttuum 3,030,224 Patented Ape-17, 1962 ice The procedure of Example I wasrepeated except 2- (3,4 methylenedioxyphenyl) 4,5 diphenylimidazole wasutilized in place of lophine. The whitening effect of2-(3,4-methylenedioxyphenyl)-4,5-diphenylimidazole was particularlynoticeable in the cotton percale and the Dacron-cotton samples.

Example 111 In order to test the wash-retention of lophine on textiles,samples of the textiles listed in Example I were subjected to fiverepeated washings in wash solutions containing lophine as described inExample I. A control sample of each textile type was then removed andthe remainder of the samples subjected to five successive washings suchas that described in Example I, except that no brightening agent wasadded to the washing solution. Comparison samples were taken after thefirst, second and fifth washings. The respective samples from thevarious washings were then line dried and visually compared with oneanother and with the control samples. These comparisons were made undernoontime light from a northern skylight. No differences could bedetermined between the textile samples from the various washings. In allcases the brightness-whiteness characteristics of the washed samplesappeared to be as good as the control samples which had been subjectedto five successive optical bleach treatments and which had not beensubjected to subsequent washing.

Example IV In order to test the wash-retention of2-(3,4-methylenedioxyphenyl)-4,5 diphenylimidazole, the procedure ofExample III was repeated with the exception that 2-(3,4-methylenedioxyphenyl)-4,5-diphenylimidazole was ultilized as the opticalbleach rather than lophine. A visual comparison of samples revealed nonoticeable difference in the brightness-whiteness characteristicsbetween the respective samples after the first, second and fifthwashings. No visual differences in brightness-whiteness could bedetermined between the control samples and the textile samples afterfive successive washings.

In the foregoing examples the optical bleach materials, lophine and2-(3,4 methylenedioxyphenyl)-4,5-diphenylimidazole, were initiallydissolved in a small amount of water made slightly acidic with formicacid. In commercial operations wherein the speed of dissolution is not arequired characteristic of the optical bleach, the use of a preliminaryacid solution may conveniently be omitted.

What is claimed is:

1. A textile material treated with an optical bleach selected from thegroup consisting of lophine and 2-(3,4 methylenedioxyphenyl)-4,5diphenylimidazole so as to cause fluorescence in a visible light rangewhen subjected to ultraviolet light. I

2. A textile material treated with lophine so as to cause fluorescencein a visible light range when subjected to ultraviolet light.

3. A textile material treated with 2-(3,4 methylenedioxyphenyl)-4,5diphenylimidazole so as to cause fluorescence in a visible light rangewhen subjected to ultraviolet light.

4. A method of producing a brightening effect upon textile materialswhich comprises treating a textile material with a solution containingan optical bleach selected from the group consisting of lophine and2-(3,4 methylenedioxyphenyl)-4,5 diphenylimidazole.

5. A method of producing a brightening effect upon textile materialswhich comprises treating a textile material with a solution of lophine.

6. A method of producing a brightening eflfect upon textile materialswhich comprises treating a textile ma terial with a solution of 2-(3,4methylenedioxyphenyl)- 4,5 diphenylimidazole.

7;; A method of producing a brightening efiect upon textile materialswhich comprises treating a textile mater'al with a solution containingbetween about 0.0001% an about 0.1% by weight of the solution of anoptical bleach selected from the group consisting of lophine and 2-(3,4methylenedioxyphenyl) -4,5 diphenylimidazole.

8. A method of producing a brightening effect upon textile materialswhich comprises treating a textile material with a solution containingbetween about 0.0001% and 0.1% by weight of lophine.

9. A method of producing a brightening effect upon textile materialswhich comprises treating a textile material with a solution containingbetween about 0.0001% and 0.1% by weight of 2-(3,4methylenedioxyphenyl)-4,5 diphenylimidazole.

10. A method of producing a brightening effect upon textile materialswhich comprises treating a textile material with an aqueous solutioncontaining between about 0.0001% and about 0.1% by weight of thesolution of an optical bleach selected from the group consisting oflophine and 2-(3,4-methylenedioxyphenyl)-4,5-diphenylimidazole, andallowing the water to evaporate.

11. A method of producing a brightening effect upon textile materialswhich comprises treating a textile material with an aqueous solution ofbetween about 0.000l% and about 0.1% by weight of the solution oflophine and allowing the water to evaporate.

12. A method of producing a brightening efiect upon textile materialswhich comprises treating a textile material with an aqueous solution ofbetween about 0.0001% and about 0.1% by weight of the solution of 2-(3,4methylenedioxyphenyl)-4,5-diphenylimidazole and allowing the water toevaporate.

10. A METHOD OF PRODUCING A BRIGHTENING EFFECT UPON TEXTILE MATERIAL WHICH COMPRISES TREATING A TEXTILE MATERIAL WITH AN AQUEOUS SOLUTION CONTAINING BETWEEN ABOUT 0.0001% AND ABOUT 0.1% BY WEIGHT OF THE SOLUTION OF AN OPTICAL BLEACH SELECTED FROM THE GROUP CONSISTING OF LOPHINE AND 2-(3,4-METHYLENEDIOXYPHENYL)-4,5-DIPHENYLIMIDAZOLE, AND ALLOWING THE WATER TO EVAPORATE. 